package main

import (
	"encoding/xml"
	"io"
	"net/http"
	"net/http/httptest"
	"os"
	"path/filepath"
	"strings"
	"testing"
)

func newTestServer(t *testing.T, files map[string]string) (*httptest.Server, string) {
	t.Helper()
	dir := t.TempDir()
	for name, src := range files {
		writeFile(t, dir, name, src)
	}
	a, err := newApp(dir, "https://posts.example.com/")
	if err != nil {
		t.Fatal(err)
	}
	srv := httptest.NewServer(a.routes())
	t.Cleanup(srv.Close)
	return srv, dir
}

func writeFile(t *testing.T, dir, name, src string) {
	t.Helper()
	if err := os.WriteFile(filepath.Join(dir, name), []byte(src), 0o644); err != nil {
		t.Fatal(err)
	}
}

func get(t *testing.T, srv *httptest.Server, path string) (int, http.Header, string) {
	t.Helper()
	resp, err := http.Get(srv.URL + path)
	if err != nil {
		t.Fatal(err)
	}
	defer resp.Body.Close()
	body, err := io.ReadAll(resp.Body)
	if err != nil {
		t.Fatal(err)
	}
	return resp.StatusCode, resp.Header, string(body)
}

var sample = map[string]string{
	"2026-01-01-oldest.md": "# Oldest\n",
	"2026-02-01-middle.md": "---\ntitle: Middle\nsummary: The middle one.\n---\nMiddle body\n",
	"2026-03-01-newest.md": "# Newest\n",
	"2026-04-01-draft.md":  "---\ndraft: true\n---\n# Secret draft\n",
	"Bad Name.md":          "# Broken\n",
	"notes.txt":            "not a post",
}

func TestIndex(t *testing.T) {
	srv, _ := newTestServer(t, sample)
	status, h, body := get(t, srv, "/")
	if status != 200 {
		t.Fatalf("status = %d", status)
	}
	if h.Get("Content-Security-Policy") == "" || h.Get("X-Content-Type-Options") != "nosniff" {
		t.Errorf("missing security headers: %v", h)
	}
	n, m, o := strings.Index(body, "Newest"), strings.Index(body, "Middle"), strings.Index(body, "Oldest")
	if n < 0 || m < 0 || o < 0 || !(n < m && m < o) {
		t.Errorf("posts missing or out of order:\n%s", body)
	}
	if !strings.Contains(body, "The middle one.") {
		t.Error("summary not shown")
	}
	for _, hidden := range []string{"Secret draft", "Broken"} {
		if strings.Contains(body, hidden) {
			t.Errorf("%q should not be listed", hidden)
		}
	}
}

func TestEmptyIndex(t *testing.T) {
	srv, _ := newTestServer(t, nil)
	if status, _, body := get(t, srv, "/"); status != 200 || !strings.Contains(body, "No posts yet") {
		t.Errorf("status = %d, body:\n%s", status, body)
	}
}

func TestPostPage(t *testing.T) {
	srv, _ := newTestServer(t, sample)
	status, _, body := get(t, srv, "/posts/middle")
	if status != 200 {
		t.Fatalf("status = %d", status)
	}
	for _, want := range []string{
		"<title>Middle · posts.example.com</title>",
		"<p>Middle body</p>",
		`<a class="newer" href="/posts/newest">`,
		`<a class="older" href="/posts/oldest">`,
	} {
		if !strings.Contains(body, want) {
			t.Errorf("missing %q in:\n%s", want, body)
		}
	}

	_, _, newest := get(t, srv, "/posts/newest")
	if strings.Contains(newest, `class="newer"`) {
		t.Error("newest post should have no newer link")
	}
	_, _, oldest := get(t, srv, "/posts/oldest")
	if strings.Contains(oldest, `class="older"`) {
		t.Error("oldest post should have no older link")
	}
}

func TestNotFound(t *testing.T) {
	srv, _ := newTestServer(t, sample)
	for _, path := range []string{
		"/posts/nope",
		"/posts/draft",
		"/posts/2026-01-01-oldest",
		"/posts/..%2f..%2fetc%2fpasswd",
		"/posts/",
		"/static/",
		"/static/missing.css",
		"/whatever",
	} {
		status, _, body := get(t, srv, path)
		if status != 404 {
			t.Errorf("%s: status = %d, want 404", path, status)
		}
		if path != "/static/missing.css" && !strings.Contains(body, "<h1>404</h1>") {
			t.Errorf("%s: expected styled 404 page", path)
		}
	}
}

func TestStatic(t *testing.T) {
	srv, _ := newTestServer(t, nil)
	status, h, body := get(t, srv, "/static/style.css")
	if status != 200 || !strings.HasPrefix(h.Get("Content-Type"), "text/css") || !strings.Contains(body, ":root") {
		t.Errorf("status = %d, type = %q", status, h.Get("Content-Type"))
	}
}

func TestFeed(t *testing.T) {
	srv, _ := newTestServer(t, sample)
	status, h, body := get(t, srv, "/feed.xml")
	if status != 200 || !strings.HasPrefix(h.Get("Content-Type"), "application/rss+xml") {
		t.Fatalf("status = %d, type = %q", status, h.Get("Content-Type"))
	}
	var feed rss
	if err := xml.Unmarshal([]byte(body), &feed); err != nil {
		t.Fatalf("invalid XML: %v\n%s", err, body)
	}
	items := feed.Channel.Items
	if len(items) != 3 {
		t.Fatalf("got %d items, want 3", len(items))
	}
	if items[0].Link != "https://posts.example.com/posts/newest" {
		t.Errorf("first link = %q", items[0].Link)
	}
	if items[1].Description != "The middle one." {
		t.Errorf("description = %q", items[1].Description)
	}
}

func TestReloadsWhenContentChanges(t *testing.T) {
	srv, dir := newTestServer(t, map[string]string{"2026-01-01-one.md": "# One\n"})
	if _, _, body := get(t, srv, "/"); strings.Contains(body, "Two") {
		t.Fatal("unexpected post")
	}
	writeFile(t, dir, "2026-01-02-two.md", "# Two\n")
	if status, _, _ := get(t, srv, "/posts/two"); status != 200 {
		t.Errorf("new post not picked up: status = %d", status)
	}
	if err := os.Remove(filepath.Join(dir, "2026-01-01-one.md")); err != nil {
		t.Fatal(err)
	}
	if status, _, _ := get(t, srv, "/posts/one"); status != 404 {
		t.Errorf("removed post still served: status = %d", status)
	}
}